Congenital heart disease

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Congenital heart disease, abbreviated CHD, is a niche area of cardiac pathology, which is a subset of cardiovascular pathology.

Paediatric cardiac surgery

Norwood procedure

Indication:

  • LHHS - following birth.

Details:

  • Pulmonary artery is attached to the aorta.
  • The lungs are perfused by a Blalock-Taussig shunt (subclavian artery -> pulmonary artery) or a Sano shunt (single ventricle -> synthetic conduit -> pulmonary artery).

Images:

Hybrid procedure
  • Is an alternative to the Norwood procedure.
  • It is call hybrid procedure as it is a mix of a surgery and a minimally invasive interventional procedure.[1]

Key elements:[2]

  1. Stent the ductus arteriosus (interventional cardiology/interventional radiology).
  2. Band the pulmonary artery - to reduce the pulmonary pressure (cardiac surgery).

Notes:

  • It appears to be associated with more GI complications.[3]

Bidirectional Glenn Shunt

  • AKA bidirectional cavopulmonary shunt (BCPS), AKA hemi-Fontan procedure, AKA bidirectional cavopulmonary anastomosis (BDCPA).[4]

Indication:

  • LHHS - following Norwood procedure, reduce work done by the heart; usu. done at age 4 to 6 months.

Details:

  • The superior vena cava (SVC) is hooked-up to the right pulmonary artery.[5]
  • The conduit connecting the ventricle and lungs (Blalock-Taussig shunt or Sano shunt) is disconnected.

Image:

Fontan procedure

  • De-oxygenated blood bypasses the heart en route to the lungs.
  • Usually done at age 2-4 years.[4]

There is the original Fontan procedure and two variants:

  • Atriopulmonary connection (the original) - right atrial appendage connected to (proximal) right pulmonary artery.[6]
  • Intracardiac total cavopulmonary connection (lateral tunnel).
  • Extracardiac total cavopulmonary connection.

Image:

Notes:

  • Fontan procedure cannot be done in a newborn as the pulmonary vascular bed resistance is too high.[6]

Shunts - overview

Most shunts are a consequence of congenital heart disease. They can be grouped into left-to-right and right-to-left.

Left-to-right

Mnemonic the Ds:[7]

  • ASD = atrial septal defect.
  • VSD = ventricular septal defect.
  • AVSD = atrioventricular defect.
  • PDA = patent ductus arteriosus.

Note: The word Left has four letters and there are four L->R shunts.

Right-to-left

Mnemonic 5 Ts:[8]

  • Tetralogy of Fallot (TOF).
  • Transposition of great arteries.
  • Truncus arteriosus.
  • Tricuspid valve atresia.
  • Total anomalous pulmonary venous return.

Clinical:

  • These babies are blue, as the blood partially bypasses the lung and/or oxygenated blood is mixed with de-oxygenated blood.
  • TOF is the classic cause of "blue babies".

Left-to-right

Ventricular septal defect

  • Common serious congenital heart defect.
    • Most common congenital defect = bicuspid aortic valve.[9]

Atrial septal defect

  • May be seen in adults.

Clinical

  • Fixed S2 split.

Classification

Types:[10]

  • Ostium secundum (most common) - between SVC and IVC.
  • Ostium primum - between SVC and IVC closer to RV.
  • Upper sinus venosus defect - at SVC.
  • Lower sinus venosus defect - at IVC.
  • Coronary sinus defect.

The ostium secundum are the most common and usually found in isolation, i.e. there are not other associated abnormalities.

Eisenmenger syndrome

General

Definition:[11]

Causes

  • ASD - rarely causes Eisenmenger syndrome.
  • VSD.
  • Extra-cardiac shunt.

Note: Eisenmenger syndrome, by definition in some sources, is (only) due to a VSD.

Microscopic

End-stage disease:[12]

  • Often characterized by fibrinoid necrosis of small pulmonary arterial vessels (arterioles & small arteries).


Right-to-left

Tetralogy of Fallot

  • Abbreviated TOF.

General

  • Most common cause of a blue baby.

Etiology

  • Abnormal septation of the truncus arteriosus.

Definition

Features:[8]

  • Right ventricular hypertrophy.
  • Right ventricular outflow tract obstruction.
  • Overriding aorta.
  • VSD (ventricular septal defect).

Notes:

  • Overriding aorta = aorta has a biventricular connection --takes blood from the right ventricle.
  • Right ventricular outflow tract obstruction is usually subpulmonic stenosis.

Transposition of great vessels

  • AKA transposition of great arteries.

General

  • Aorta and pulmonary trunk hooked-up to the wrong ventricle.
    • Survivable after birth only if there is a functional shunt, e.g. (persistent) patent ductus arteriosus and/or atrial septal defect.
    • When the ductus arteriosus closes they are in trouble.

Total anomalous pulmonary venous return

  • Abbreviated TAPVR.

General

  • Pulmonary veins do not attach to left atrium.
  • Classified by where the veins attach.[13]

Other

Left hypoplastic heart syndrome

Defintion:[14]

  • Physiologically inadequate left ventricle.

Key characteristic:[15]

  • Atrial septal defect (ASD) -- left-to-right shunt.

Causality:

  • Mitral stenosis.
  • Left ventricular hypoplasia.

Associations:[15]

  • Turner syndrome.
  • Noonan syndrome - sometimes called "male version of Turner syndrome".
  • Smith-Lemli-Opitz syndrome.
  • Holt-Oram syndrome.[16]


Splenic abnormalities

Asplenia is associated with cardiac abnormalities:[17]

  • Aspenia = Boys, Bad congenital malformations (transposition of great vessels, pulmonary atresia/stenosis, totally anomalous pulmonary return).
    • Interesting is that these are all right-to-left shunts.

For completeness... polyspenia associations:[17]

  • Polyspenia = Girls, Good prognosis, Gastrointestinal situs inversus.

Cor pulmonale

Pulmonary hypertension due to heart disease.

Pulmonary hypertension

Pressure - definition:[11]

  • Mean pulm. arterial pressure >25 mmHg at rest.

See also

References

  1. URL: http://www.childrenshospital.org/views/august05/cardiacsurgery.html. Accessed on: 14 January 2011.
  2. URL: http://www.childrenshospital.org/views/august05/cardiacsurgery.html. Accessed on: 14 January 2011.
  3. Weiss SL, Gossett JG, Kaushal S, Wang D, Backer CL, Wald EL (December 2010). "Comparison of Gastrointestinal Morbidity After Norwood and Hybrid Palliation for Complex Heart Defects". Pediatr Cardiol. doi:10.1007/s00246-010-9864-9. PMID 21188371.
  4. 4.0 4.1 Alsoufi B, Bennetts J, Verma S, Caldarone CA (January 2007). "New developments in the treatment of hypoplastic left heart syndrome". Pediatrics 119 (1): 109–17. doi:10.1542/peds.2006-1592. PMID 17200277. http://pediatrics.aappublications.org/cgi/content/full/119/1/109.
  5. GLENN WW (July 1958). "Circulatory bypass of the right side of the heart. IV. Shunt between superior vena cava and distal right pulmonary artery; report of clinical application". N. Engl. J. Med. 259 (3): 117–20. doi:10.1056/NEJM195807172590304. PMID 13566431.
  6. 6.0 6.1 Fontan F, Baudet E (May 1971). "Surgical repair of tricuspid atresia". Thorax 26 (3): 240–8. PMC 1019078. PMID 5089489. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1019078/.
  7. Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 566. ISBN 0-7216-0187-1.
  8. 8.0 8.1 Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 568. ISBN 0-7216-0187-1.
  9. Siu SC, Silversides CK (June 2010). "Bicuspid aortic valve disease". J. Am. Coll. Cardiol. 55 (25): 2789–800. doi:10.1016/j.jacc.2009.12.068. PMID 20579534.
  10. http://en.wikipedia.org/wiki/File:ASD.png
  11. 11.0 11.1 Jensen AS, Iversen K, Vejlstrup NG, Hansen PB, Sondergaard L (April 2009). "[Eisenmenger syndrome]" (in Danish). Ugeskr. Laeg. 171 (15): 1270-5. PMID 19416617.
  12. Daliento L, Rebellato L, Angelini A, et al. (2002). "Fatal outcome in Eisenmenger syndrome". Cardiovasc. Pathol. 11 (4): 221-8. PMID 12140128.
  13. URL: http://emedicine.medscape.com/article/899491-overview. Accessed on: 10 March 2011.
  14. Moore. TDH. P.361
  15. 15.0 15.1 http://emedicine.medscape.com/article/890196-overview
  16. Ekure EN, Okoromah CN, Briggs E, Ajenifuja OA (September 2004). "Holt-Oram syndrome with hypoplastic left heart syndrome in an African child". Niger Postgrad Med J 11 (3): 190–2. PMID 15505648.
  17. 17.0 17.1 Rose V, Izukawa T, Moes CA (August 1975). "Syndromes of asplenia and polysplenia. A review of cardiac and non-cardiac malformations in 60 cases withspecial reference to diagnosis and prognosis". Br Heart J 37 (8): 840-52. PMC 482884. PMID 1191445. http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=482884&pageindex=1#page.